How to mockup your post height increase with Gimp/Photoshop

We go through this tutorial by screenshots so it be illustrative than purely theoretical which might mess up, I didn't wanted to spam with too large screenshots, so for preview you'll see medium size image, click on link right below the image to see its full size and observe better.

We consider out 3d model as 175cm, we be lengthening it for 5cm making it as 180cm

1. I chose below 3d model to do this mock-up

https://i.imgur.com/nZB8zQJ

2. Duplicate this image into two, so we use one to determine the height and then discard and start using other copy, so duplicate your image into two

3. Crop image from ankles to top of your head, note in image we are not including whole feet we just need from ankle to head top

https://i.imgur.com/jg0u6ZS

4. After having right selecting of crop, now crop this image

https://i.imgur.com/pvlgdbG

5. Check for size of this image(Top bar -> Image -> canvas size in gimp software), in below image we got height as 348px(pixels) divide this with height 348px/175cm = 1.988571429px as per this each cm in this image represent 1.988571429px

https://i.imgur.com/zDzGaJE

6. Discard this cropped image after we have our calculations, we are left with other copy make another duplicate of it, so we have two copies of 3d model

7. Open new layout with extra height than your original image(I choose 520px for this image) copy our 3d model to this layout, now you have it as this, and select half the image(from tibia or femur as per your requirement, here we doing for tibia), we use this selection to separate this 3d model into two pieces

https://i.imgur.com/VPDTMmi

8. Cut the select of which we made

https://i.imgur.com/jGoZGnG

9. Paste the top part of 3d model, above the bottom part leave the gap in-between

https://i.imgur.com/m6c7SCK

10. From previous calculations we know each cm in our image represent 1.988571429px, we need to lengthen 5cm that is 5cm*1.988571429px = 9,942857145px, make a selection of this amount from tibia or femur as per your requirement, in this example we doing it with tibia, we made crop selection for 10px(gimp didn't allow me to use value i calculated so I gone with 10px), as you can see in red marked location(this is gimp software)

https://i.imgur.com/U4IRwkU

11. Hit crop we get our lengthened part as below, copy this and paste it into our image from image of step number 9 as third part

https://i.imgur.com/QwK85ej

12. Align the third part with bottom part of image, as below

https://i.imgur.com/jxkVWT0

13. Bring down the top part to join the image as below

https://i.imgur.com/9wexjSX

You have successfully created a mock up increasing 5cm

Hello Nomad,
Thank you for the tutorial. I finally managed to understand all the steps except for one issue. At the very end (Step 12), at the point when I align all parts- cropped part (from tibias where I added the desired length), the width doesn't blend well with the rest. How do you manage to align them and have a smooth result? Based on the outcome of your 3d model, I also see there the same problem? Have you found a way to overcome this when you worked with your actual image ?

Quote from: gigaki on February 27, 2020, 10:37:34 PMHello Nomad,
Thank you for the tutorial. I finally managed to understand all the steps except for one issue. At the very end (Step 12), at the point when I align all parts- cropped part (from tibias where I added the desired length), the width doesn't blend well with the rest. How do you manage to align them and have a smooth result? Based on the outcome of your 3d model, I also see there the same problem? Have you found a way to overcome this when you worked with your actual image ?

Step 12, isn't that complicated but i can understand following it all at once could be bit intimidating and confusing, Step12, is simple you have three image parts,
i. Upper body, ii, Lower body, iii. lengthened part of tibia/femur, you have to keep them one over other just as puzzle so you look at yourself post lengthening, widths don't match 100% as you see even in my 3d model they don't, but its a small image so its more noticeable when you do it with some big enough one it be less noticeable but still won't be perfect, it can only serve the purpose of going your some rough clue of how you would look.


Sorry for late reply been bit busy these days